In the process of production of semiconductor devices, an electronic device test system is necessary for testing the finally produced IC chips or other electronic devices. This type test of electronic device is executed by inputting a test pattern to the IC chip under test, operating it and inspecting the response pattern in the state with the test environment set a temperature environment of an ordinary temperature, high temperature, or low temperature.
A general electronic device test system comprises: a tester storing a program for sending out a test pattern and inspecting a response pattern; a test head having contact terminals for electrically connecting this tester and an IC chip under test; and a handler successively conveying IC chips under test to the contact terminals and physically classifying the finished tested IC chips under test in accordance with the test results. Further, IC chips under test are set in the handler, are conveyed to the test head, and are pushed against the contact terminals to electrically connect them so as to execute the desired operational test.
The test head of such an electronic device test system comprises a large number of pin electronics cards (device mounted apparatus) used as interfaces for the input/output terminals of the IC chips under test. Each pin electronics card is formed by mounting a mensurative high frequency circuit, power circuit, or other various devices on a board. As the high frequency circuit mounted on a pin electronics card, an analog comparator circuit receiving an analog response signal output from an IC chip under test and converting it to a logic signal by the desired threshold voltage, a high precision timing judgment circuit, etc. may be mentioned. These circuits correspond to the IC chip under test.
The various devices of a pin electronics card become high in temperature due to the heat they generate at the time of testing IC chips under test. Therefore, as a pin electronics card able to cool devices generating heat on their own, one covering the front and back surfaces of the board by a cover and making a refrigerant flow inside the cover to bring the refrigerant into direct contact with the heat generating devices has been known in the past (for example, see Patent Document 1).
However, in this pin electronics card, a single board is provided with a cover at the front and back. All of the devices mounted on the same board are covered by the same cover. Therefore, the current generated in the cover due to the electromagnetic waves etc. radiated from the power circuits is propagated as noise to the high frequency circuits, a drop in the S/N ratios of the high frequency circuits etc. is caused and a securing of high precision tests of IC chips under test becomes difficult in some cases. Further, depending on the timing of generation of the noise source or frequency component, sometimes the test quality will fluctuate for the IC chips under test.
Further when conducting a test by a desired high precision while a high frequency circuit applies and receives an analog signal or high frequency signal to and from an IC chip under test, sometimes interference noise is caused along with the high frequency circuit applying and receiving a strong level or very weak level signal and other circuits are covered by the same cover. As a result, it sometimes becomes difficult to secure high precision tests.
[Patent Document 1] WO2005/004571